1. Field
The present application relates generally to communication, and more specifically to filters.
2. Background
Wireless communication devices typically must transmit and receive signals in accordance with regulatory requirements that may vary between geographical regions. As a result, wireless communication devices must either be specifically manufactured for a particular region or must be able to operate in accordance with the regulatory requirements of multiple regions. Receivers and transmitters include signal filters for attenuating unwanted signals and noise. Receivers within wireless communication devices typically include a front end and a back end where the front end includes a front end filter for filtering the incoming spectrum to minimize the amplitude of undesired signals while passing the desired signals. The front end filter, therefore, should minimize attenuation of signals of the receive band and maximize attenuation of signals outside the receive band. In addition to front end filters, receivers may include other interstage filters within the receiver lineup. Regulatory requirements often dictate the characteristics of the front end filter due to the differences in the location and size of the receive band and the differences in restrictions in the location and authorized energy of transmitted signals and spurious emissions near or within the receive band. Conventional wireless communication devices either include a front end filter that meets the requirements of a specific region or include multiple front end filters. These conventional techniques are limited in that some devices may only operate in certain regions and that they result in increased manufacturing cost.
Therefore, there is need for a communication device with an adjustable filter.